Incorporating Assumptions for TDM Impacts in a Regional Travel Demand Model

Faced with substantial funding shortfalls in meeting transportation needs, one of Washington State Department of Transportation’s key strategies for preserving mobility is improving the efficient operation of the existing transportation facilities by increasing the use of transportation demand management (TDM) strategies to decrease drive alone rates. This requires an ability to forecast the magnitude and geographic distribution of changes in travel patterns likely to result from more aggressive TDM programs. It also requires an ability to estimate the effect these changes will have on delay, speed, and travel time throughout affected corridors. This project developed a Transportation Demand Management Assessment Procedure (TDMAP), as a sketch planning modeling approach to incorporate TDM into WSDOT’s travel demand model. TDMAP does so by (1) extracting mode split tables from the model; (2) processing them to be compatible with TRIMMS© 2.0, an existing tool that estimates changes in travel behavior as a result of implementing different TDM strategies; (3) running the tables through TRIMMS© 2.0; and then (4) processing them back into the four-step model for distribution over the transportation network. The study did develop a low cost method to help WSDOT plan TDM strategies as part of its overall transportation planning process. Ideally, the next generation would also help WSDOT identify and choose the most cost-effective mix of program elements for improving traffic and air quality conditions in a corridor, and for the desired level of change in vehicle traffic, and see how the cost and mix varies with the desired level of change. Building such a tool requires additional research, and improved data on the cost and effectiveness of TDM program elements under different conditions. Recommendations for research and data development to help bring this goal to fruition were made.

Publication Date: 
Tuesday, March 30, 2010
Publication Number: 
WA-RD 746.1
Last modified: 
10/12/2016 - 15:41
Phillip L. Winters, Edward L. Hillsman, Chanyoung Lee, Nevine Labib Georggi.
University of South Florida. Center for Urban Transportation Research
Number of Pages: 
Travel demand management, Traffic models, Congestion management systems, Transportation system management, Travel behavior, Transportation facility operations, Transportation planning, Travel patterns, Cost effectiveness.